5,386 research outputs found

    Measuring the Willingness to Pay for Fresh Water Cave Diving

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    Fresh water springs are unique natural resources that are contained within public lands across the United States. Natural resource management on public lands generates many interesting policy issues as the competing goals of conservation, recreational opportunity provision, and revenue generation often clash. As demand for recreational cave diving sites increases, the paper provides natural resource site managers with the first statistical estimate of divers’ willingness to pay to dive fresh water cave and cavern systems. Using a contingent valuation model approach and correcting for hypothetical bias, we find that divers’ median willingness to pay for cave diving opportunities at the site of interest is approximately $68 per dive. Model results also provide evidence of diver sensitivity with respect to scope as individuals are willing to pay more for dives that are higher in quality. Key Words: Contingent Valuation Model; Willingness to Pay; Cave Diving; Scope Sensitivity

    Using Revealed and Stated Preference Data to Estimate the Scope and Access Benefits Associated with Cave Diving

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    In a single-site travel cost model framework, revealed and stated preference data are jointly estimated to provide the first use value estimate associated with recreational cave diving. Focusing on one of Florida’s first magnitude springs, we estimate average per-person per-trip use values of approximately 165,generatingannualcavedivingusevaluesinexcessof165, generating annual cave diving use values in excess of 1,150. Further, in an investigation of potential site quality changes, we find that divers are sensitive to scope effects with an additional cave system increasing annual per-person use values by approximately 130,whileimprovedaccessyieldsanadditional130, while improved access yields an additional 57 in per-person annual consumer surplus. Finally, three additional model specifications are estimated and indicate that divers use different travel cost preferences when assessing their revealed and stated preference trip counts but a single preference structure to evaluate site quality changes. Key Words: Revealed and Stated Behavior; Scope Effects; Access; Travel Cost Preferences

    Analyzing the Fierz Rearrangement Freedom for Local Chiral Two-Nucleon Potentials

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    Chiral effective field theory is a framework to derive systematic nuclear interactions. It is based on the symmetries of quantum chromodynamics and includes long-range pion physics explicitly, while shorter-range physics is expanded in a general operator basis. The number of low-energy couplings at a particular order in the expansion can be reduced by exploiting the fact that nucleons are fermions and therefore obey the Pauli exclusion principle. The antisymmetry permits the selection of a subset of the allowed contact operators at a given order. When local regulators are used for these short-range interactions, however, this "Fierz rearrangement freedom" is violated. In this paper, we investigate the impact of this violation at leading order (LO) in the chiral expansion. We construct LO and next-to-leading order (NLO) potentials for all possible LO-operator pairs and study their reproduction of phase shifts, the 4{}^4He ground-state energy, and the neutron-matter energy at different densities. We demonstrate that the Fierz rearrangement freedom is partially restored at NLO where subleading contact interactions enter. We also discuss implications for local chiral three-nucleon interactions.Comment: 11 pages, 5 figure

    PrAGMATiC: a Probabilistic and Generative Model of Areas Tiling the Cortex

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    Much of the human cortex seems to be organized into topographic cortical maps. Yet few quantitative methods exist for characterizing these maps. To address this issue we developed a modeling framework that can reveal group-level cortical maps based on neuroimaging data. PrAGMATiC, a probabilistic and generative model of areas tiling the cortex, is a hierarchical Bayesian generative model of cortical maps. This model assumes that the cortical map in each individual subject is a sample from a single underlying probability distribution. Learning the parameters of this distribution reveals the properties of a cortical map that are common across a group of subjects while avoiding the potentially lossy step of co-registering each subject into a group anatomical space. In this report we give a mathematical description of PrAGMATiC, describe approximations that make it practical to use, show preliminary results from its application to a real dataset, and describe a number of possible future extensions

    Searching for t-bar t Resonances at the Large Hadron Collider

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    Many new physics models predict resonances with masses in the TeV range which decay into a pair of top quarks. With its large cross section, t-bar t production at the Large Hadron Collider (LHC) offers an excellent opportunity to search for such particles. We present a detailed study of the discovery potential of the CERN Large Hadron Collider for Kaluza-Klein (KK) excitations of the gluon in bulk Randall-Sundrum (RS) models in the t-bar t -> ell^+/- nu b-bar bq-bar q' (ell=e, mu) final state. We utilize final states with one or two tagged b-quarks, and two, three or four jets (including b-jets). Our calculations take into account the finite resolution of detectors, the energy loss due to b-quark decays, the expected reduced b-tagging efficiency at large t-bar t invariant masses, and include the background originating from Wb-bar b+jets, (Wb+W-bar b)+jets, W+jets, and single top + jets production. We derive semi-realistic 5 sigma discovery limits for nine different KK gluon scenarios, and compare them with those for KK gravitons, and a Z_H boson in the Littlest Higgs model. We also analyze the capabilities of the LHC experiments to differentiate between individual KK gluon models and measure the couplings of KK gluons to quarks. We find that, for the parameters and models chosen, KK gluons with masses up to about 4 TeV can be discovered at the LHC. The ability of the LHC to discriminate between different bulk RS models, and to measure the couplings of the KK gluons is found to be highly model dependent.Comment: revtex3, 27 pages, 5 tables, 6 figure

    NASCAR Sponsorship And Shareholder Return: Some Preliminary Results

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    NASCAR sponsorship is a major investment for corporations that choose it as a marketing communication tool. Companies frequently spend in excess of $10 million to sponsor a car in the Nextel Cup series. This paper develops a return on investment measure for that spending using the financial market event study methodology where race day performance influence on publicly traded sponsoring firm’s stock returns is examined. Results for the 2005 NASCAR Nextel Cup season suggest that sponsorship of top 5 finishing cars generates significant positive returns for the sponsoring company shareholders

    Endangered Species Act Reauthorization: Congress Proposes a Rewrite with Private Landowners in Mind

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    Diving Demand for Large Ship Artificial Reefs

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    Using data drawn from a web-based travel cost survey, we jointly model revealed and stated preference trip count data in an attempt to estimate the recreational use value from diving the intentionally sunk USS Oriskany. Respondents were asked to report their: (i) actual trips from the previous year, (ii) anticipated trips in the next year, and (iii) anticipated trips next year assuming a second diveable vessel (a Spruance class destroyer) is sunk in the same vicinity. Results from several different model specifications indicate average per-person, per-trip use values range from 480to480 to 750. The “bundling†of a second vessel in the area of the Oriskany to create a multiple-ship artificial reef area adds between 220and220 and 1,160 per diver per year in value.Artificial reefs, diving, recreation demand, combined revealed and stated preferences, non-market valuation, Institutional and Behavioral Economics, Marketing, Productivity Analysis, Public Economics, Research Methods/ Statistical Methods, Q26, Q50,
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